UHV Sputtering System for the Deposition of Ultrathin Films and Heterostructures

• Subject Area: Condensed Matter Physics
• Term: Funded in 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 517957243

The availability of thin films and heterostructures with tailored properties is essential for many fundamental physics experiments. For example, the particular transport effects in materials with topologically non-trivial band structure, pure spin currents in magnetic insulators, or magnetoresistive effects in antiferromagnetic heterostructures can only be studied in appropriate samples. The thin film deposition system proposed here consists of two ultra-high vacuum sputtering chambers – one for the deposition of metallic films in an inert atmosphere, one for the production of oxide layers in a reactive or oxidizing environment – connected by a load lock. The two separate sputtering chambers enable the deposition of high-purity metallic or oxidic layers using optimum process parameters, without contamination or degradation of other materials in the chamber. In addition, the samples can be transferred from one sputtering chamber to the other via the load lock without breaking the vacuum, so that metal/oxide heterostructures with very clean "in-situ" interfaces can be fabricated. Such heterostructures are essential for the investigation of spin transport phenomena in electrical insulators. In particular, we want to study the influence of magnetic order (paramagnetic, ferrimagnetic, antiferromagnetic, etc.) on pure spin transport phenomena in suitable metal/oxide heterostructures. To this end, we intend to establish the deposition of crystalline substituted iron garnet layers, in which the magnetic ordering temperature and other magnetic properties can be tuned at will. This enables systematic spin transport, spin dynamics and spin fluctuation experiments in different magnetic phases and across phase boundaries. For the investigation of magnetic fluctuations, ultra-thin (few monolayers thick) films or heterostructures with perpendicular anisotropy are also of interest, which are only accessible with a state-of-the-art deposition system. In addition, we intend to investigate large transverse transport effects (anomalous Hall or Nernst effect, spin Hall effect, etc.) in certain antiferromagnetic crystals and topologically non-trivial materials, which again requires the fabrication of suitable thin films or heterostructures. Finally, in the medium term, the integration of superconducting and magnetic layers would allow studying the local magnetic and electronic properties of such interfaces in a spatially resolved manner, and to possibly exploit corresponding spin-electronic functionalities. In summary, the UHV sputtering system proposed here opens up qualitatively new possibilities for the deposition of thin layers and heterostructures, thus forming a basis for successful research work in the coming years.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: UHV-Sputtersystem zur Herstellung von ultradünnen Filmen und Heterostrukturen
• Instrumentation Group: 8330 Vakuumbedampfungsanlagen und -präparieranlagen für Elektronenmikroskopie
• Applicant Institution: Universität Konstanz
• Leader: Professor Dr. Sebastian Gönnenwein